Creating Effective Charts Through the Strategic Use of Colour

I recently gave a talk at the Women in Data Science Ibadan Conference 2020 on communicating Data Effectively (find the slides here). One of the things I emphasized was that creating effective charts that will immediately grab the attention of the audience, focusing their attention where you want it to be for quick understanding, requires the use of certain visual qualities called preattentive attributes. One of such is colour.

A data visualization expert does not just use colour for the sake of creating colourful charts. Rather, she leverages the power of colour to call attention to the important elements of the visual. Colour should always be used strategically. In her book, Storytelling with Data, Cole Knaflic advised that colour should be used sparingly, consistently and with the colourblind in mind. The visualization expert should be mindful of the tone colour conveys and know when to leverage brand colors.

One of the ways in which colour can be strategically used is in providing contrast so as to immediately draw eyes to where you want the audience to focus their attention to. This means that we cannot afford to use too many colours so that information is not lost. A maximum of two colours is advisable.

Below is an example of a scenario where colour was used to provide contrast that draws attention to the main information:

Where were your eyes drawn?😊

Mine was immediately drawn to the green bar indicating the percentage of farmers using television as their information source. After which I moved on to the takeaway messages.

In addition, I have also intentionally used the colour green because of the topic I was discussing which was centred on agriculture.

These are some of the ways in which colour can be employed to convey the necessary information and set a tone that matches the topic in order to communicate your data effectively.